1. Technical Field
The embodiments of the present disclosure are related in general to the field of installation of supports for uprights of fences, traffic signs, real estate signage, etc., and in particular to post supports that can be permanently installed, and from which one post can be removed and another emplaced.
2. Description of the Related Art
Posts of various lengths and compositions are used in a wide range of applications, including supporting fences, traffic control signs, temporary structures, etc. Where a post is intended to be substantially permanent, it is often placed in a hole and anchored in a concrete footing to increase its cross section and hold it firmly in place. One problem that is commonly encountered in such situations is that posts, especially wooden posts, are subject to breakage, warpage, and decomposition. Replacing a post that has been anchored in concrete is difficult, wasteful, and unfriendly to the environment for reasons that include excessive use of natural resources and the generation of landfill material. The concrete footing must be removed from the ground in order to make room for the new post. This requires that a much larger hole must be dug around the concrete footing. In turn, this requires a much larger volume of concrete or re-compaction of the surrounding soil, to fill the hole around the new post and create the new footing in proper contact with undisturbed or adequately compacted soil.
One of the most common causes of deterioration in wooden posts is water trapped around the end of the post inside the concrete. For example, when the post is damp or wet for an extended period of time, the wood absorbs water and draws it by capillary action downward into the concrete footing. Water becomes trapped between the wood and the inside wall of the concrete, so that the end of the post remains wet even while the upper portion is dry. This is especially true in cases where the end of the post is completely encapsulated in concrete, preventing water from escaping through the bottom of the footing, in which case the majority of the water escapes only through the wicking action of the end grain of the post.
To reduce this problem, installers often pour several inches of gravel into the bottom of a post hole and place the post directly on the gravel before they pour concrete around it. This prevents the concrete from completely sealing up the bottom of the post by flowing under it, and thus provides a channel for water to escape into the gravel. However, this is only a partial solution. Often the drainage gravel is not fully compacted and settles, causing more need for repair and replacement. Furthermore, with this common method, it takes substantial time for water, once having entered the footing, to work its way all the way through the footing and out the bottom. If the post is subjected to frequent or extended wet periods, the end of the post inside the footing may remain constantly wet even though water continues to drain out the bottom. Additionally, because of the direct contact with the ground on the end of the post, water can move upward into the footing when the ground is wet due to the capillary or wicking effect of the end grain. This constant dampness encourages the growth of organisms that digest the wood fiber and eventually destroy the post, or in the case of steel, rusts the post away. Additionally, the bottom of the footing is substantially open to insects, which can enter unobstructed from the gravel below to attack and eat the post.
Furthermore, direct contact between concrete and some species of wood generates a reaction that promotes deterioration of the wood. This limits the species of wood that can be used for fence or sign posts where concrete footings will be used in direct contact with the post.
Another approach that is used to protect wood posts and other lumber in direct contact with the ground or with concrete is commonly referred to as pressure treating. In this process, protective chemicals are forced into an outer surface of the post under high pressure. The chemicals provide the post with protection from common funguses and other organisms that cause deterioration. Pressure treatment generally extends the useful life of a post by a factor of five to ten. However, the chemicals used in pressure treatment are often toxic to humans and non-target organisms, and can leach into the water supply. In other cases, the chemicals are highly corrosive, tending to cause corrosion in fasteners and structures that are attached thereto. An additional problem with pressure treatment is that the wood cannot generally be recycled when it is replaced, and should not be composted, because of the chemicals still present. This means that it must be deposited in a landfill which in turn is a result of the need to install a post in direct contact with the ground and or concrete.
A third approach to this problem is the use of prefabricated anchors or sleeves, i.e., pockets that are placed in the ground or anchored in a concrete footing. These anchors permit a post to be removed and replaced without requiring that the pocket itself be replaced. Some examples of such anchors are disclosed in the following U.S. patents, all of which are incorporated herein by reference in their entireties: U.S. Pat. No. 5,632,464; U.S. Pat. No. 6,098,353; and U.S. Pat. No. 7,325,790.